This application is not referenced in any microfiche appendix.
1. Field of the Invention
This invention teaches new and unexpected cross linking of several chemically different types of polymers by combining selected chemical moieties into a mixture which will cross link the chemically different polymer types. This invention further teaches the development of a new type of polymer with or without the cross linking chemical mixture which offers unexpected results. Both or either the new cross linking mixture and or the new polymer may be useful in many different industrial applications. Examples as to modify asphalts or bitumens are shown herein to illustrate utility of the teachings.
2. Prior Art
Previous to the invention disclosed herein, most known prior art centered upon various techniques for modification of asphalt by polymer combinations with no regard for direction of polymer chemistry to encompass all possible aspects of polymer structure. Rather, prior polymer art generally teaches one facet of polymer chemistry and structure as related to polymer usage such as modified asphalt. The art disclosed herein will set forth unexpected results by understanding the effects of combining the various possible polymer chemistry and structure interactions and relationships to polymer modified asphalt. This understanding of the various polymer chemistries and structures will be further augmented and disclosed herein by the unexpected results obtained with the use of a universal cross linking agent. By universal cross linking agent, it is meant that combinations of chemical moieties disclosed herein form mixtures which may be adjusted in ratio or by inclusion or exclusion of any chemical moiety disclosed herein to form a cross linking agent to optimize the effect of a cross link of various polymer chemistries and structures to themselves for industrial applications such as with asphalt or bitumen.
It has long been known in the rubber industry that from vulcanization, elemental sulfur will under go revision upon prolonged heating. It is also known that phenolic resin derivatives and in particular phenol formaldehyde derivatives do not as easily under go revision as sulfur. It is further understood in the art that the presence of Group VII-A elements (the so called Halides) of the Periodic Table of Elements will enhance the resistance of degradation of phenolic resin vulcanization to revision. The Group VII-A Elements may be present as attached to the phenolic ring of a phenol aldehyde or introduced separately in a salt form with Group IV-A Elements of the Periodic Table. Typical of this understanding is the paper entitled xe2x80x9cThe Vulcanization of Butyl Rubber with Phenol Formaldehyde Derivativesxe2x80x9d by P. O. Tawney, J. R. Little and P. Viohl and presented at the Division of Rubber Chemistry meeting of the American Chemical Society on May 14-16, 1958 in Cincinnati, Ohio and is here in incorporated by reference. As will be shown in this disclosure, a direct application of the use of Group IV-A salts of Group VII-A Elements of the Periodic Table of Elements through the salt form will not yield satisfactory results when combined in phenol aldehyde polymer asphalt mixtures. Taught in this disclosure will be the unexpected results of combining metal sulfates and metal chloride (salts with phenol aldehyde resols resins in the presence of polymer asphalt mixtures).
U.K. Patent No. 368,236 issued to Robert Bosch Aktiengesellschaft found they could use phenol aldehyde condensation products catalyzed in the usual way with optional rubber and asphalt. The product is a plastic, not asphaltic in final usage, suitable for acid and electrical resistance applications. This art lacks discussing mix temperature parameters or processing except to state the use of a mixing machine or by rollers.
Russian Patent No. 732340 issued to Main Pipelines Construction teaches that a phenol formaldehyde resin may be used in a primer composition for pipe coatings. The teachings limit the phenol formaldehyde resin to 2.0% to 10.0% by weight in the formula. All materials are dissolved in a hydrocarbon solvent at room temperature or with gentle heating. There is no disclosure for cross linking the phenol formaldehyde resin or that it is of the reactive type.
The Russian Patent No. 761527 issued to Polymer Construction Material teaches the use of pentachlorophenol resin in solvent based systems. The teachings of the art limit bitumen to 65.0% to 70.0% in terms of weight percent. It is not stated that the pentachlorophenol is of a reactive form or made reactive for use in cross linking reactions. Pentachlorophenol is normally not reactive and is used to improve aging and or tack. The butyl rubber is described in detail as follows: the molecular weight ranges from 13,000 to 27,000 containing 1.5% to 1.9% vinyl groups, 0.20% to 0.25% secondary amino groups and 0.25% to 0.30% hydroxyl groups. The product of the process is for pipe coatings.
In German Patent No. DE 3630132A issued to J. Haas is taught that cross linking agents may be formed by combining sulfur in plasticizer oil with oxidants, vulcanization auxiliary agents or other combinations. This art also teaches that the sulfur containing vapor may be collected as filter material and reused in the next batch.
The U.S. Pat. No. 3,275,585 issued to Baum et al. and assigned to Mobil Oil Corporation disclosed the aldehyde as the main source of polymeric material and does not teach or disclose the use of any type or rubber or other elastomeric materials. The use level of the aldehyde of from 1 to 25% and preferably 5 to 15% based upon the weight of the asphalt. A strong mineral acid catalyst, hydrochloric or toluene sulfonic acid for example, is at the 0.1% to 5.0% and preferably 0.1 to 2.0% use level based upon the weight of the asphalt. There is no discussion of reactions of, with or by cross linked carboxylic acid terminated vinyl aromatic/conjugated diene polymers with a universal cross linking compound suitable for cross linking various polymer types.
In U.S. Pat. No. 3,547,805, inventor Montgomery teaches the use of alkali metals to polymerizing in situ conjugated dienes and vinyl substituted aromatic compounds. The preferred alkali metal is sodium. The preferred diene is 1,3-butadiene. The preferred vinyl substituted aromatic compound is styrene. Characteristics of the process are changes or increases in ring and ball softening point and higher penetration ratio. The penetration ratio is defined in column 3, line 1 through line 3 as the ratio of the penetration at 39.2xc2x0 F. (4xc2x0 C.) to the penetration at times 100 as determined by ASTM Test Method D5-61.
Prior art by Krivohlavek, U.S. Pat. No.5,256,710 teaches that carboxylated styrene butadiene and similar types of rubber polymers without carboxylation in use with one and two step phenolic curing resins with or with out the presence of sulfur or sulfur donors or accelerators activated by or catalyzed by heat or amines (Hexamethylene tetraamines as a specific example) may be used to modify or cross link polymer modified asphalt. This work did not address further polymer chemistry or the use of metal chlorides or sulfates. Klutz in U.S. Pat. No. 5,278,207 and U.S. Pat. No. 5,322,867 teaches the use of various poly amine compounds to crosslink carboxylic acids grafted to pre formed styrene butadiene block copolymers to be used in asphalt modification. In the art disclosed by Klutz, various acrylic acid or methacrylate or melaic moieties are used as a source for grafting a carboxylic acid or anhydride to the polymer backbone. Gorbathy, U.S. Pat. Nos. 5,288,773 and 5,336,805 and 5,348,994 disclose the potential for sulfonation of styrene butadiene block copolymers and subsequent cross linking by amines or metallic compounds in the presence of asphalt.
Gorbathy also taught in U.S. Pat. No. 5,336,705 the utility of acrylic acid terpolymers with sulfonated rubber such as EPDM and styrene butadiene in the presence of oxidized asphalt and neutralized (or cross linked) by cations having +1 to +3 valence. A typical acid terpolymer is given in EXAMPLE 1, column 9, lines 11, 12 and 13 as 1% acrylic acid and 23% methyl acrylate and melt index equal to 5.
Moran, et al. teaches that mineral acids may be used to help make various polymers such as ethylene vinyl acetates more compatible with asphalts in U.S. Pat. Nos. 4,882,373 and 4,873,275 and 5,095,055 and alpha-olefins in U.S. Pat. No. 5,393,811 collectively.
Societe Chimique Des Charbonnages a French Body Corporate of Tour Aurore Cedex 05,92080 Plaris LaDefence, France in United Kingdom Patent No. 1,534,182 teaches that ethylene vinyl acetate copolymers may be cross linked with various combinations of acids, metal alcoholate and boric acid (borax) and possibly in the presence of elemental sulfur.
Saito et.al. in U.S. Pat. No. 4,292,414 teaches that carboxylic acids grafted to styrene in styrene butadiene block polymers may be cross linked with various multivalent metal oxides but does not teach the utility of such in asphalt.
Fisher in U.S. Pat. No. 5,190,998 addressed the art of improving or increasing elastic recovery by the presence of 10% or greater 1,2 vinyl content in homopolymers of polybutadiene and free of sulfur or peroxide cross linking agents.
Maldanado teaches the use of carboxylated styrene butadiene block copolymers in vulcanization with sulfur in U.S. Pat. No. 4,330,449 attributing improvement to reversible salt formations with asphalt metal ions. There is no discussion of the addition of metal ions to the asphalt rubber mixture or as a part of a vulcanization step.
Maldonado et al. in U.S. Pat. No. 4,145,322 disclosed the use of sulfur with primarily styrene butadiene block copolymers. There were no other cross linking systems disclosed or taught. Van Reijendam et al. disclosed in U.S. Pat. No. 4,011,184 that bitumen-polymer compositions may be improved by chemically coupling a modified bitumen and a modified polymer with a metal compound. Both the bitumen and the polymer are modified with ethylenically unsaturated carboxylic acids or their anhydrides before combination. The metal compound may be from Groups I to IV of the Periodic Table as given in claim 1.
Fitoussi et.al. disclose in U.S. Pat. No. 4,237,052 grafting dihalopolybutadiene receptors to asphalt modified with block copolymers. Elastomers may be polystyrene and butadiene or similar and a vulcanizable polynoroborene. Sulfur may serve as a covulcanization agent. This patent does teach multiple vulcanization routes with in the same polymer family of polynoroborene but does not teach the use of a universal cross linking agent or compound for other types of polymers with or in asphalt.
Mancini taught the use of dicarboxylic acids or anhydrides of those acids to be reacted in polymers of styrene butadiene styrene (claim 7) in asphalt in U.S. Pat. No. 5,225,462. Mancini also taught a 190 to 240xc2x0 C. process temperature was needed for improved properties.
Marzocchi et al. taught in U.S. Pat. No. 4,301,051 and U.S. Pat. No. 4,404,316 that a chemically modified asphalt be prepared by reacting polymerizable vinyl monomers and a rubbery polymer. Cross linking reactants such as epoxies and organic polyisocyantes may be used with hydroxy terminated polybutadiene components in asphalt. Additionally, carboxylic acids or their anhydrides may be used as cross linking reactants.
Kriech et al. disclosed a type of gelled asphalt cement in U.S. Pat. No. 4,874,432 comprised of at lease one fatty acid and at least one resin acid with an alkali metal base there by limiting the amount of water necessary to form a gel. The product of the process is said to improve temperature susceptibility of asphalts.
Gelles et al. teaches in U.S. Pat. No. 5,189,083 the use of methacrylic acid (a alkyl methacrylate) in polymer formations involving aromatic vinyl hydrocarbons and conjugated dienes such as styrene and butadiene respectfully to form acid or acid anhydride blocks within the polymer structure. These polymers are subsequently used to modify asphalt. High vinyl content within the conjugated dienes is presumably for hydrogenation of the vinyl component as no claims or examples are set forth as to utility in further cross linking through vinyl component unsaturation. Gelles et al. further state in column 2 lines 38 and 39 that xe2x80x9cEnd capping does not provide a high level of functional groups.xe2x80x9d While this is obviously true, there is then a lack of understanding of the value of cross linking functional group end capped polymer chains in conjunction with cross linking through vinyl diene component unsaturation of a polymer. Further bearing out this lack of understanding is evidenced in column 8 lines 16 through 19 where in conventional cross linking approaches or (not xe2x80x9candxe2x80x9d or xe2x80x9cbothxe2x80x9d) cross linking through methacrylate derivative groups may be utilized. There is no art taught nor are there any examples of combining multiple cross linking features available through the polymer chemistry.
Doyle et al. in the series of U.S. Pat. Nos. 5,437,717 and 5,476,542 and 5,496,400 teaches that a improved cross linking agent may be created which is substantially anhydrous by combining tall oil, a strong base, fatty amines and either n-methyl fatty acid taurate, anhydrous catenary ammonium chloride or di-ethyl sulfate quat. This mixture may be used either alone in the asphalt or in asphalt which has been modified by ground tires. Doyle et al. does not address issues related to polymer chemistry or structure.
The prior art does not teach the unexpected utility of cross linking various polymer chemistries with a universal cross linking agent. Prior art does not teach the unexpected utility of combining components of polymer chemistry in a orderly manner to maximize the advantages of a universal cross linking agent.
The invention disclosed herein relates to a new and novel cross linking agent resulting from the combination of a mixture of various chemical moieties and may be used in polymer modified asphalt or bitumen. Further distinction of this new cross linking agent over previously disclosed art is the unexpected ability to cross link with polymers of differing chemical composition and the resulting vastly different polymer classes or types which may be in the presence of asphalt or bitumen. The development of this new cross linking agent offers improvements to a polymer asphalt or bitumen blend previously not easily attained or expected. These improvements are as a result of physical property improvements to asphalt or bitumen polymer blends.
Related to the invention of the new and novel cross linking agent is the unexpected find and development of the new cross linking agent with a new type of polymer. Previously, those schooled in polymer modified asphalt or bitumen had available to them polymers with limited means of cross linking within the asphalt. The new type of polymer disclosed and invented as a result of these teachings distinguishes itself by unexpected improvement within the polymer asphalt or bitumen mixture either alone or in conjunction with previously known cross linking agents or with the new cross linking agent related to this disclosure.